[Gluster-users] Possible to use libgfapi with libvirt in CentOS 6.5?

Lalatendu Mohanty lmohanty at redhat.com
Fri Mar 28 14:47:28 UTC 2014


On 03/28/2014 07:26 PM, SATHEESARAN wrote:
> On 03/28/2014 05:37 PM, Dave Christianson wrote:
>> I've come across individual posts from people who supposedly have 
>> done this in CentOS6.5. Basically, all that is shown in the posts is 
>> the XML file generated, no mention of *how* that file is generated. 
>> Virt-manager has no provision for attaching directly to the gluster 
>> volume except as a mount. Neither virt-manager nor virt-install 
>> recognize the gluster:// type.
> Yes, even I was frustrated at this. There seems no way to utilize the 
> image file using libgfapi.
> As Harsha mentioned in his earlier thread, libvirt is yet to expose this.
> I have already raised a bug regarding this, 
> https://bugzilla.redhat.com/show_bug.cgi?id=1017308
>> Supposedly earlier versions of RHEL used qemu-kvm as a wrapper for 
>> qemu-system-x86_64, however in 6.5 qemu-kvm is its own binary. 
>> Qemu-kvm also doesn't recognize the gluster:// type.
> With RHEL 6.5 / Centos 6.5 you can use, "/usr/libexec/qemu-kvm"
> This was the command that I used to make use of VM Images using 
> libgfapi in RHEL 6.5
> >> /usr/libexec/qemu-kvm  -drive 
> file=gluster://10.70.37.87/testvol/test.img,if=none,id=drive-virtio-disk0,format=qcow2,cache=none,werror=stop,rerror=stop,aio=threads 
> -device 
> virtio-blk-pci,scsi=off,bus=pci.0,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=0
>
> The above worked for me.
> If I am not wrong, the libvirt in RHEL 7 supports glusterfs's libgfapi 
> way of access mechanism.

Sas,

What about Fedora 20? Fedora 20 should have all the latest RPMs , so it 
should  have required patches in libvirt too.

-Lala
>
>
>>
>> Debian and Ubuntu supposedly have the newer versions of gluster and 
>> qemu/libvirt availabe (ppa's?). Maybe I'll test Wheezy...
>>
>> Red Hat seems content to do their own thing. Although the verisons of 
>> libvirt and qemu are older, libgfapi is supposed to have been 
>> backported. It's a shame that full functionality is not included. 
>> It's mindboggling seeing that Red Hat owns glusterfs, you would think 
>> full support for the backend would have been included in their 
>> product. If it is, as you say, that RH includes this functionality 
>> only to RHN subscribers and is not made available downstream to 
>> CentOS/SL, and unless I can find a repository with the latest full 
>> versions of qemu & libvirt, then CentOS simply will not work.
>>
>>
>> On Fri, Mar 28, 2014 at 3:13 AM, Harshavardhana 
>> <harsha at harshavardhana.net <mailto:harsha at harshavardhana.net>> wrote:
>>
>>     Virt-manager / libvirt is yet to expose perhaps this functionality -
>>     but as far as i remember libvirt should be doing this as a
>>     pass-through for the URL's which have been passed  as
>>     "<schema>://<server>/<volname>"
>>
>>     Does libvirt 'invoke' fuse when passed "gluster://" schema?
>>
>>     On Thu, Mar 27, 2014 at 5:34 PM, Dave Christianson
>>     <davidchristianson3 at gmail.com
>>     <mailto:davidchristianson3 at gmail.com>> wrote:
>>     > Good Evening,
>>     >
>>     > I have read that libgfapi has been backported to qemu-kvm in
>>     RHEL 6.5 (and
>>     > by virtue CentOS and SL). However I am unable to figure out how
>>     to actually
>>     > make it work as described. Virt-manager still only seems to support
>>     > glusterfs volumes via fuse.
>>     >
>>     > I can use qemu-img to create a disk image on
>>     gluster://<server>/<Volume>.
>>     > But virt-manager can only use it from a fuse mounted fileshare.
>>     There seems
>>     > to be no ability to attach in virt-manager directly to the image on
>>     > glusterfs using libgfapi.
>>     >
>>     > All documents I've found describe the use of the command
>>     > "qemu-system-x86_64," however that command does not exist in
>>     CentOS 6.5.
>>     > That appears to be the only way to start the domain using
>>     libgfapi. So
>>     > basically, I can create an image via libgfapi but cannot do
>>     anything useful
>>     > with it.
>>     >
>>     > Should I be able to do this? If so, what's the procedure? Or is
>>     CentOS/RHEL
>>     > 6.5 just not fully integrated? I really want to be able to use
>>     libgfapi and
>>     > avoid the performance penalty of fuse. Should I just grab &
>>     compile the
>>     > latest verisons of libvirt and qemu-kvm?
>>     >
>>     > _______________________________________________
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>>
>>
>>
>>     --
>>     Religious confuse piety with mere ritual, the virtuous confuse
>>     regulation with outcomes
>>
>>
>>
>>
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